Sfera Labs has begun shipping the Strato Pi Plus, a DIN-rail industrial edge server based on the Raspberry Pi 4B or Raspberry Pi 5. The system adds a 10–50 V DC power supply, up to four isolated RS-485 interfaces, CAN FD connectivity, and an independent RP2354 microcontroller.

According to the Strato Pi Plus documentation, the hybrid architecture pairs the Raspberry Pi with the RP2354, which operates separately from the main processor and handles system supervision, hardware watchdog functions, power-cycle control, RS-485 transmit enable, relay control, fan management, and input-power monitoring. This arrangement allows the controller to detect an unresponsive Raspberry Pi and initiate a recovery without relying on software running under Raspberry Pi OS.

The co-processor communicates with the Raspberry Pi over I²C, while Linux drivers expose its controls and monitored parameters through the sysfs interface. Sfera Labs also supports in-field RP2354 firmware updates through the Raspberry Pi GPIO interface, and developers can replace the standard firmware with a custom implementation when required.

Strato Pi Plus dimensions top view

Depending on the selected configuration, the Strato Pi Plus provides up to four individually galvanically isolated RS-485 ports. Each interface uses an Analog Devices ADM2861E transceiver supporting data rates up to 500 kbps, with software-configurable termination, local echo, and A/B polarity inversion.

Variants equipped with CAN use a Microchip MCP2518FD controller and MCP2558FD transceiver. The interface supports CAN 2.0B and CAN FD, with data rates up to 8 Mbps during the data phase and 1 Mbps during arbitration. CAN termination can also be enabled programmatically.

Strato Pi Plus dimensions side view

The system is available in three main configurations. Variant A includes four RS-485 interfaces, CAN FD, and a relay; Variant B reduces this to one RS-485 interface while retaining CAN FD and the relay; and Variant C provides a single RS-485 interface. Raspberry Pi 4B and Raspberry Pi 5 versions are offered with memory capacities reaching 16 GB, along with optional active cooling.

The wide-range power input accepts 10–50 V DC and includes surge protection, reverse-polarity protection, and a 3.3 A resettable fuse. The internal supply can deliver up to 30 W through its primary 5 V regulator, while pluggable 3.81 mm terminal blocks provide access to power, serial buses, CAN, and the optional relay.

Strato Pi Plus RTC backup battery

Additional hardware includes an NXP PCF2131 real-time clock with a replaceable backup battery and a Microchip ATECC608 secure element for hardware-based key storage and cryptographic operations.

An optional three-axis IIS2DLPC accelerometer can be used for tamper detection, vibration monitoring, or impact sensing, while the optional fan is controlled by the RP2354 using configurable temperature thresholds.

Strato Pi Plus

Standard Raspberry Pi connectivity remains accessible, including Gigabit Ethernet, four USB ports, Wi-Fi, Bluetooth Low Energy, microSD storage, and the display outputs provided by the installed Raspberry Pi model.

The assembly is housed in a four-module DIN-rail enclosure with front-mounted status LEDs for power, user-defined functions, RS-485 activity, and CAN traffic.

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